With improvements in science and technology and market expansion, the satellite communication industry is developing rapidly. In the field of the satellite communication, the requirement for the reliability, the quality and the volume of aerospace products is very strict. High reliability and miniaturization are the developing trends for aerospace products. An input multiplexer is the communication satellite device indispensable to achieve the channelization of broadband signals. The existing input multiplexer utilizes electric cables or waveguide, circulator to connect channel filters, which causes such problems as big volume, heavy mass, low reliability and lack of consistency among channels.